Tonya Couch, center, is taken by authorities to a waiting car after arriving at Los Angeles International Airport on Thursday in Los Angeles. (Mark J. Terrill / Associated Press)

The mother of a Texas teenager known for using his wealthy upbringing, or "affluenza," as a defense in a fatal drunk driving case will appear in a downtown Los Angeles courtroom Tuesday morning, where authorities will request she be extradited back home, police said.

Tonya Couch, 38, was flown to Los Angeles in the middle of the night last week after she and her son, Ethan Couch, 18, were caught in Puerto Vallarta, Mexico, where the teen had been on the lam for an alleged probation violation.

The teen's mom is accused of helping her son flee the country and hide. She's being held in county jail until she is sent back to Texas to face charges, authorities said. Her hearing is scheduled for Tuesday morning, an LAPD official said.

Couch and her son were considered international fugitives after he failed to show up for a probation hearing.

In 2013, when he was 16, Ethan Couch struck and killed four pedestrians near Forth Worth while driving drunk. Prosecutors wanted Couch to serve 20 years in prison.

Instead, he was sentenced to rehab and probation after a defense expert argued in juvenile court that Couch suffered from "affluenza" — an inability to tell right from wrong because he had a spoiled upbringing and wealthy parents who never punished him for bad behavior.

The terms of his 10-year probation forbid him from driving or consuming alcohol.

But on Dec. 2, a Twitter user posted a six-second video that appeared to show Couch, now 18, clapping and grinning at a party where young men were playing beer pong.

"Ya boy ethan couch violating probation," tweeted the user, @BlondeSpectre, tagging the Tarrant County district attorney's office. With a blast of angry and sardonic keystrokes, she added, "Ethan Couch? more like Ethan Ouch you killed my family and suffered no consequencjaldjwldjkz."

Couch and his mother disappeared shortly afterward. They were found last week in the Mexican resort town of Puerto Vallarta after they ordered pizza and authorities traced the call.

Ethan Couch remains in custody in Mexico and is fighting extradition to the U.S.

Richard Hunter, chief deputy U.S. marshal for the southern district of Texas, said that a three-day injunction granted to Couch would probably take at least two weeks to resolve. But such legal maneuvers to block deportation from Mexico can drag on for months.

Though Couch is now legally an adult, his case is still being handled in juvenile court in Texas. Under Texas juvenile law, even if he is returned to the U.S. and is found to have violated his probation, Couch may have to spend only up to 120 days in jail.